ISIS and Al Qaeda are enemies – that we knew before Paris and Copenhagen. Russia is not an enemy, in the sense of an opponent with which we are at war. True, there are sanctions in place against Putin’s Government, but in some ways it is almost an ally: its co-operation in relation to Afghanistan and Iran and extreme Sunni Islamist movements is actively sought.

But make no mistake: if the campaign for higher defence spending led by Peter Luff, James Arbuthnot and Bob Ainsworth succeeds, it is unlikely to be because David Cameron or Ed Miliband decide to prepare for another adventure in the Middle East or in Muslim-majority countries elsewhere. It will be to ready ourselves to respond to military action by Putin against other NATO member nations.

It is a bad thing to have to deal with two antagonists at once. Which is more of a threat to our national interest? Is it Russia launching a conventional war (albeit with asymmetric action too) in eastern Europe? Or is it the threat of terror from Islamists on our streets? Should our priority be to build up our conventional forces for action abroad, or to have security forces poised for rapid response here at home?